The present invention concerns a calendar mechanism in a watch, including a first and a second indicator which are each associated with a rotating wheel set provided with a toothing, a drive lever provided with two beaks arranged for acting respectively on the toothing associated with the first or second indicator, depending upon the pivoting direction of the drive lever, to make the corresponding indicator move forward one step, a drive wheel making one revolution per day and provided with a drive element which cooperates with a cam surface of the drive lever to make said lever pivot each day in one direction and the other from a neutral position and thus make said beaks act on said toothings, and manual correction means for making the first and second indicators move forward step by step independently of each other,
A mechanism of this kind, disclosed in U.S. Pat. No. 2,720,746, daily activates a date indicator and a day indicator in a miniature clock, owing to a lever with two arms whose ends each carry a click cooperating with a peripheral toothing of the indicator disc concerned. This lever includes a hole whose sinuous contour forms a cam surface and in which a cam follower runs carried by a wheel that makes one revolution per day. This results in a very simple drive mechanism for the indicators. However, correction of the calendar indicators requires two correction devices, independent of the daily driving and each associated with the respective indicator, which increases the total space requirement of the mechanism and requires two manual correction members.
FR Patent No. 1 517 236 discloses a calendar mechanism with date and day indicators that can be used in a watch and which also includes a common drive element for both indicators, this element having a hole of complex shape in which a drive finger rotates. In this embodiment, the drive element makes a combination of sliding and pivoting movements. A device for correcting the date by means of the time setting stem is also provided, which is completely independent of the drive element.
There is also known, from CH Patent No. 584 926, a common correction mechanism for the date and day indicators from the winding stem of a watch, while the daily driving of said indicators is performed by other members. Here too, the common element that acts sometimes on the first indicator and sometimes on the second makes a combination of sliding and pivoting movements.